Transformation on CdS→CdCO3 Thin Films by Chemical Bath and CdCO3→CdO Annealing Thermal in Atmosphere Air

CdS and CdCO3 thin films were grown onto glass by chemical bath deposition (CBD). The temperature of the bath (Td) was selected at 80°C and 20°C, respectively. CdCO3 were annealed in at air atmosphere an normal pressure for 0.5 h. Scanning Electron Spectroscopy (SEM), X-ray diffraction (XRD), optical absorption (OA), measurements were carried out to characterize the layers. Using the SEM grown layers: Td = 80 °C concentration atomic: Cd = 49.10, S = 51.90, for Td = 20 °C, increase of carbon and oxygen: Cd = 12.8, C= 20.0, O = 67.2. CdCO3 annealing thermal in atmosphere air: Cd = 49.8, O = 50.2. We analyzed the morphological of the films. Patterns XRD show that the layer with Td = 80 °C, CdS in Wurzite (W) phase. Td = 20 °C Peaks at 2ԕ = (23.4, 30.2, 36.4, 40.1, 43.8, 48.0, 49.5, 49.9, 58.2, 61.7, 62.9, 65.5), CdCO3 which has rhombohedral crystalline. CdCO3 annealing 120 °C completely disappeared and only peaks of CdO are identified. All of the peaks in this pattern has pure cubic phase of CdO: 2ԕ = (33.1, 38.2, 55.3, 59.9. 69.3). The average grain size (GS), calculated from the main XRD peak by CdCO3 reduce of 30.5 nm reaching 12.8 nm respectively, was calculated by employing Scherer's formula. The forbidden band gap energy for: CdS Eg = 2.48 eV, CdCO3 Eg = 3.87 eV, and CdCO3 annealed (CdO) Eg = 2.31 eV.